Dialysis Catheter

ABSTRACT

A catheter assembly includes catheter having proximal and distal ends and at least one lumen extending between the ends. At least one end of the catheter is formed from a material that can be trimmed to achieve a selected length for the catheter. A tubular connector is telescoped over the catheter and a hub is joined to the tubular connector. Proximal portions of the hub are configured for connection to a medical apparatus. A cuff is mounted around the tubular connector or the catheter. The cuff is formed from a material that will permit or promote the growth of scar tissue for anchoring the catheter device at least on a semi-permanent basis in a patient.

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/807,575, which in turn is a divisional of U.S. patentapplication Ser. No. 11/287,789 now U.S. Pat. No. 7,258,685.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a catheter that can be used for dialysis or forother procedures where the catheter is implanted for an extended periodof time.

2. Description of the Related Art

Dialysis and some chemotherapy regimens require a catheter to beimplanted in a patient for an extended time (e.g., several weeks,several months or longer). Catheters for dialysis extend from anexternally accessible location on the patient (typically on the chest)to a location where there is a high flow of blood (typically near theheart). The high blood flow enables a sufficient volume of blood to beprocessed through the catheter and cleaned by the dialysis machine.Catheters used for chemotherapy and other drug administration purposesare extended from an externally accessible location on the patient to alocation where the drug is likely to be most effective. The followingdiscussion will pertain mostly to catheters intended for dialysis.However, the subject invention is applicable to all catheters that areimplanted for an extended time.

A discussion of catheters is provided in Venous Catheters A PracticalManual by Pieters et al. Chapter 4 of that work is entitled CentralVenous Catheters: Materials, Designs and Selection by Matthew A. Mauro,and the disclosure of that Chapter 4 is incorporated herein byreference.

Briefly, the distal end of a dialysis catheter should be placed close tothe heart for optimum exchange of blood. Doctors typically want to knowthe location of the distal end of the dialysis catheter withconsiderable precision. The proximal end of the dialysis catheterdesirably is at a location that can be accessed conveniently duringdialysis and that is unobtrusive between the periodic dialysisprocedures. Many doctors choose to direct the dialysis catheter throughthe jugular vein. However, the neck certainly is not the unobtrusivelocation for keeping the proximal end of the dialysis catheter betweenthe periodic dialysis procedures.

The dialysis catheter typically is formed from a flexible material, suchas silicone. A typical medical procedure for implanting a dialysiscatheter involves first placing a small incision in the skin of the neckover the jugular vein. Subsequently, the jugular vein is cannulated. Apeelable introducer sheath then is advanced an appropriate distance intothe blood vessel so that the end of the catheter is at the preciseposition preferred by the doctor. The doctor then employs a tunneldilator to create a subcutaneous tunnel that permits the proximal end ofthe catheter to be at a less obstrusive position. The subcutaneoustunnel typically extends slightly below the skin from a location on thechest and under the clavicle to a location where the catheter has beenintroduced into the jugular. The doctor directs the catheter through thetunnel, to the neck, through the incision in the neck and through theintroducer sheath. The introducer sheath then is removed. A hub at theproximal end of the catheter may include a Luer fitting that enables theproximal end of the catheter to be placed in communication with thedialysis machine. Several closure means are provided on or near theproximal end of the catheter to prevent unintended blood loss betweenthe periodic dialysis procedures.

Blood pressure and other forces within the body tend to urge thecatheter from the body. Hence, proper anchoring is important. One commonanchoring means provides a cuff extending around the portion of thecatheter in the tunnel that extends from the upper chest to the neck ofthe patient. The cuff typically is formed from polyester. Scar tissueaccumulates around the cuff and functions to hold the catheter in place.The scar tissue may also function as a barrier to bacterial infection.The scar tissue results in at least a semi-permanent anchoring of thecatheter. In this regard, semi-permanent means that the catheter willremain in the patient until the cuffed portion of the catheter isdissected from the patient. This dissection can be complicated.

Dialysis catheters vary considerably from one manufacturer to another.However, a common requirement for virtually all dialysis catheters is anability to locate the distal end of the catheter and the cuff withconsiderable precision. Accordingly, the doctor has limitations on thedistance between the distal tip of the catheter and the cuff dependingupon physical characteristics of the patient. A smaller patient willrequire a smaller tip-to-cuff distance, while a larger patient willrequire a larger tip-to-cuff distance. In view of these physicaldifferences between patients, most dialysis catheter manufacturersprovide catheters with different tip-to-cuff length. Accordingly,hospitals must maintain an appropriate inventory of different lengthdialysis catheters and the doctor must ensure that a catheter ofappropriate length is available for implementation. There are costs andcomplications associated with a need to maintain an inventory ofdifferent products.

Compromises often must be made when a doctor selects a dialysis catheterfrom an inventory of catheters with different lengths. In this regard,dialysis catheters often come with tip-to-cuff lengths of 19 cm, 23 cm,28 cm and 32 cm. A selection of a catheter of one of these lengths mayrequire the doctor to move the tip or the cuff from its optimalposition.

Arrow Cannon markets a dialysis catheter with most of the featuresdescribed above. The Arrow Cannon catheter is promoted as having anability to assure accurate tip placement. In this regard, the tip of thecatheter is placed in the jugular in the manner described above.Proximal portions of the catheter then are urged in a retrogradedirection through the tunnel from the neck to the selected location onthe chest. The portion of the catheter emerging from the chest then iscut. A compression cap and compression sleeve are mounted separately tothe cut proximal end of the catheter and a hub is threadedly engagedwith the compression cap. The above-described Arrow Cannon catheter hasthe above-described problems associated with inventory management.Additionally, even though the tip may be positioned accurately, the cufflocation is dependent upon the different tip-to-cuff dimensions in theinventory. Additionally, the retrograde movement of the catheter throughthe tunnel requires a technique that many doctors are not accustomed to.Furthermore, the intraoperative assembly of the compression sleeve withthe compression cap requires more procedural steps and takes additionaltime.

U.S. Pat. No. 5,989,213 relates to a dialysis catheter with a guide tubethat fits into the blood vessel. A tissue ingrowth member is secured toproximal portions of the guide catheter for affixation to thesubcutaneous tissue. Thus, distal portions of the guide catheter of U.S.Pat. No. 5,989,213 reside in the blood vessel and proximal portions ofthe guide catheter are secured to the subcutaneous tissue. The dialysiscatheter then is passed through the guide catheter. The distal end ofthe dialysis catheter is disposed at an appropriate location in thecirculatory system, and distally of the distal end of the guidecatheter. Proximal ends of the dialysis catheter are disposed externallyon the patient, and proximally of the proximal end of the guidecatheter. The system shown in U.S. Pat. No. 5,989,213 permits a desireddistance between the distal tip of the catheter and the tissue ingrowthcuff. However, the system shown in U.S. Pat. No. 5,989,213 is nottrimmable and hence requires an extensive inventory of catheters ofdifferent length to ensure that an excess of the catheter is notdisposed externally of the patient.

Accordingly, it is an object of the subject invention to provide animproved catheter that can be implanted for an extended time, such as adialysis catheter.

Another object of the subject invention is to provide a catheter thatsubstantially avoids the need to maintain a significant inventory, whilepermitting precise positioning of both the tip and the cuff.

A further object of the invention is to provide a catheter that isconvenient to implant and that ensures a precise exit site on the chestfor the catheter.

SUMMARY OF THE INVENTION

The subject invention is directed to a catheter assembly. The assemblyincludes a catheter with a proximal end, a distal end and at least onelumen extending therethrough. Catheters intended for use with a dialysisapparatus preferably include at least two lumens extending between theproximal and distal ends. In this context, the distal end of thecatheter is considered to be the end that is positioned at anappropriate location in the patient, such as in a major blood vesselnear the heart. The proximal end of the catheter is considered the enddisposed externally of the patient and near the doctor who is performingthe implantation. At least the proximal parts of the catheter are formedfrom a material that is easily trimmable.

The catheter assembly further includes a means for promoting growth oftissue for fixing the catheter at a selected location relative to asubcutaneous tunnel formed for implantation of the catheter. The meansfor promoting growth of tissue may be formed from or treated with afibrosing agent. Fibrosing agents include, but are not limited to silk,collagen, talc, talcum powder, beryllium, copper, silica, quartz, EVA,PLA, polyurethane and polymerized drug compositions. Preferably themeans for promoting growth of tissue comprises a cuff mounted around ornear the catheter either intraoperatively or immediately prior toimplantation. The cuff preferably has a first orientation where the cuffis movable relative to the catheter and a second orientation where thecuff is fixed relative to the catheter. For example, the cuff initiallymay be a substantially linear structure with opposite first and secondends. The cuff is deformable or deflectable from the initial linearcondition into an annular condition. Additionally, the opposed ends ofthe cuff are securely connectable to one another so that the cuff can besecured around the catheter. The dimensions of the cuff are selected toensure secure mounting of the cuff around the catheter withoutconstricting the flow of fluid through the catheter. The structure forlocking the opposite ends of the cuff together may includeinterengageable teeth such as the interengagement employed on a wirewrap. Alternatively, the opposed ends of the cuff can have a projectionand an aperture respectively that engage much in the manner of adovetail connection. The connection and mounting of the cuff may besimilar to the connection and mounting of band clamps, hose clamps, tubeclamps, J-type clamps, one-ear clamps, two-ear clamps and other clampsthat secure a flexible member around the outer circumference of acylindrical member. Such connectors are shown in the MSC IndustrialSupply Co. catalog, the disclosure of which is incorporated herein byreference.

The cuff may be engaged directly on the catheter. However, a preferredembodiment includes a subcutaneous tube that is telescoped over theproximal end of the catheter, and the cuff is engaged around portions ofthe subcutaneous tube that are telescoped over the proximal end of thecatheter. The proximal end of the catheter and the subcutaneous tube mayhave smooth tubular surfaces that telescope into engagement with oneanother. The assembly may then include a compression cap and acompression sleeve. A Luer hub can be threaded into engagement with thecompression cap to deform the compression sleeve sufficiently forinterengagement with the catheter and the subcutaneous tube. Thecompression sleeve preferably is pre-assembled with the compression capin a manner that substantially prevents axial movement between thecompression sleeve and the compression cap while permitting thecompression sleeve to rotate relative to both the catheter and thecompression cap. Hence, the doctor is not required to assemble thecompression sleeve with the compression cap intraoperatively orimmediately prior to implementation. Additionally, the ability of thecompression sleeve to rotate relative to the compression cap and thecatheter prevents the creation of a torque that could twist andconstrict or damage the catheter. Various other optional connectionsbetween the catheter and the subcutaneous tube may be similar tocouplings in the above-referenced MSC Industrial Supply Co. catalog, thedisclosure of which is incorporated herein by reference.

An alternate version of the catheter assembly may include may include acuff tube with a proximal end, a distal end and a lumen extendingbetween the ends. The lumen is configured so that the cuff tube can betelescoped over proximal portions of the catheter. The above describedcuff may be mounted to an appropriate location on the outer periphery ofthe cuff tube. In this regard, the cuff tube can be formed with surfaceconfigurations on the outer periphery for positioning and holding thecuff. In other embodiments, the cuff may be premounted to a selectedlocation on the cuff tube. The premounting of the cuff on the cuff tubecan be achieved, for example, by adhesive. The cuff tube further mayinclude a hub mounting structure at a location on the outer peripherynear the proximal end. Additionally, the cuff tube may include means forconstricting portions of the cuff tube into a secure mechanical andfluid tight engagement with the catheter. The hub of this embodiment isconfigured for secure mounting over proximal portions of the cuff tube.The mounting may be achieved by a snapped engagement of the hub mountingstructure on the cuff tube with corresponding structure on the hub. Theassembly of this embodiment is employed by initially positioning thecatheter as described above. The cuff tube then is slid over proximalportions of the catheter and the attachments means near proximal portionof the cuff tube are tightened to achieve secure engagement of the cufftube with the catheter. Portions of the catheter that extend proximallybeyond the cuff tube then are trimmed. The hub then is mounted over andsecured to the cuff tube. The hub can be configured to mount over orinto proximal portions of the cuff tube. Additionally, engageableregions of cuff tube and the hub can be configured to compress the cufftube or the hub inwardly to achieve a secure mechanical and fluid tightinterconnection between the cuff tube, the catheter and the hub. Thisembodiment can avoid the need for a separate attachments means to securethe cuff tube to the catheter.

Another preferred embodiment of the invention provides a catheter with aproximal end configured with a plurality of undulations. Each undulationmay include a conically sloped proximal face and a radially aligneddistal face. The catheter may be employed with a hub having an innertubular surface with internal undulations configured for mating with theouter surface configuration on the proximal end of the catheter. Theconical and radial surfaces on the undulations on the catheter and thehub are oriented and configured so that the catheter and the hub can betelescoped together easily (i.e., engagement of the conical surfaces),but cannot be separated (i.e., engagement of the radial surfaces). Theabove-described cuff can be mounted around either a portion of thecatheter or a portion of the hub. The hub may include a notch foraffixing the cuff at a fixed axial position on the hub.

In an alternate embodiment, the proximal end of the catheter can beformed with an array of external threads and the interior of the hub canbe formed with an array of internal threads that can be mated with thethreads on the catheter. The cuff can be the above-described cuff thatinitially is substantially linear and that is mounted subsequentlyaround the catheter or the hub. Alternatively, the cuff can be providedwith its own internal array of threads for mounting over the proximalend of the catheter or over the hub.

The hub can include an array of external threads and a cap or nut can bethreaded over the hub. In this embodiment, the proximal end of thecatheter can merely be inserted axially into the hub. The cap or nutthen is rotated about the hub and is configured to compress the hub intoengagement with the proximal end of the catheter. In this embodiment,the cap or nut preferably includes known structure for permittingrotation in one direction while preventing or complicating rotation inthe opposed direction so that the cap or nut will not dislodgeunintentionally. For example, the threads on the cap and the hub may beconfigured to deform and substantially lock as the cap or nut isrotated. Alternatively, a biased arrangement that requires both axialand rotational movement can be provided in much the same manner as thearrangements provided on a childproof medicine bottle.

A further embodiment of the subject catheter assembly may include a duallumen catheter with opposite proximal and distal ends defining a lengthsufficient to conform to the maximum anticipated length of the requiredcatheter for all patients. A cuff is mounted fixedly and permanently tothe catheter near the proximal end. The distal end of the catheter thenmay be trimmed to the specific required length. One of the two lumensthen is cut to a shorter length than the other. If necessary or desired,the two different length lumens may be separated slightly from oneanother near the distal end. Thus, a catheter of the precise appropriatelength is assured. Additionally, the distal ends of the lumen arepositioned properly relative to one another to ensure a good flow ofblood to and from the dialysis machine, and to ensure that the recentlycleaned blood is not recirculated back directly into the dialysismachine.

In certain embodiments, the cuff can be a continuous ring that is slidover the catheter after the distal tip of the catheter has beenpositioned properly in the patient, but before the proximal portions ofthe catheter are advanced through the tunnel. In this regard, theassembly may include a longitudinally slit tube that can be mounted overa proximal portions of the catheter. This slit tube then can be employedto advance the cuff distally to a proper position. The opposedlongitudinal edges of the slit tube then can be secured together forproperly holding the slit cylindrical tube to the catheter and forproperly positioning the cuff on the catheter. Inner circumferentialsurfaces of the slit tube may include a layer of resilient material toassure a liquid tight seal against the catheter.

As noted above, a patient eventually may reach a point where furtherdialysis is unnecessary. However, the scar tissue that intentionally isdeveloped around the cuff can complicate efforts to remove the cuff andspecifically requires significant dissection. The catheter assembly ofthe subject invention can be used with a cuff removal tool. The cuffremoval tool may include a short cylindrical tube with proximal anddistal ends. The distal end of the tube may be formed with an array ofdistally directed teeth. The proximal end of the tube may include ahandle to facilitate gripping and rotation of the tube. The tube may bea slit cylinder that can be closed into a complete cylinder. Thecylindrical tube is in its open condition for mounting on the catheteror hub. The tube then can be urged into its closed position. Rotation ofthe cylindrical tube will cause the teeth at the distal end of the tubeto cut through the scar tissue around the cuff so that the catheter canbe removed with relative ease. This tube can be use with any of theabove described embodiments of the catheter assembly as well as withprior art catheters.

The catheter assembly of the subject invention has several advantagesover known structures and assemblies. In particular, there is no need tokeep an inventory of catheters of various lengths. Catheters of themaximum optional length can be provided with all assemblies and can betrimmed immediately preoperatively or intraoperatively to the preciserequired length.

Catheters can become blocked or infected. Most prior art devices requiresurgical removal of the cuff to replace the blocked or infectedcatheter. However, the assembly of the subject invention permitsreplacement of the catheter without dissecting the biologically securedcuff from the patient. In this regard, the compression cap or otherattachment means can be disengaged so that the catheter can be separatedand replaced without affecting the securely mounted cuff.

The catheter assembly of the subject invention also provides theoperator with complete control of the catheter tip and the tunnel exitsite positions. This distinguishes from prior art devices wherecompromises may have to be made on either the location of the tip or theexit site depending upon the length of the catheter chosen by thedoctor.

As noted above, most doctors prefer the more common antegrade movementof the catheter through the tunnel. However, doctors familiar with theArrow Cannon devices may have acquired familiarly with a retrogrademovement of the catheter through the subcutaneous tunnel. The catheterassembly of the subject invention permits both antegrade or retrogradetunneling techniques, and hence permits doctors to employ the techniquewith which they have become most familiar.

Many patients eventually will reach a point where the catheter is nolonger needed. Removal of the prior art catheter can be complicated insome prior art devices depending upon the positioning of the proximalend of the catheter. However, the proximal end of the catheter of thesubject assembly is always reliably near the subcutaneous tunnel exit,and hence can be accessed easily for removal of the catheter.

As noted above, a dialysis catheter is intentionally in communicationwith a high volume blood vessel. Accordingly, bleeding from the tunnelexit site remains a potential problem. However, the hub extension of thesubject invention is configured to prevent bleeding from the tunnel exitsite. Additionally, the hub extension provides an additional layer ofprotection for the catheter against ascending bacteria.

A further variation of the invention includes a catheter, as describedabove, an outer subcutaneous tube, a cap, a hub and an innersubcutaneous tube. The outer subcutaneous tube and the cap each haveopposite proximal and distal ends and a lumen extending between theends. The proximal end of the outer subcutaneous tube is connectedpermanently to the cap so that the lumen through the outer subcutaneoustube communicates with the lumen through the cap. Thus, the outersubcutaneous tube and the cap define an integral subassembly. Portionsof the outer subcutaneous tube adjacent the distal end are intended tobe placed in a subcutaneous tunnel formed in the patient. Thus, afibrous cuff or other fibrosing agent is disposed around the outercircumferential surface of the outer subcutaneous tube at locations nearthe distal end. The inner subcutaneous tube also has opposite proximaland distal ends and a lumen extending between the ends. The proximal endof the inner subcutaneous tube is connected permanently to the hub sothat the inner subcutaneous tube and the hub define an integralsubassembly. The lumen of the inner subcutaneous tube is configured forslidably receiving the catheter. Portions of the inner subcutaneous tubeadjacent the distal end have an outer circumferential dimensionconfigured to be received closely in the lumen of the outer subcutaneoustube. Additionally, the hub and the cap are configured to be connectedreleasably after the inner subcutaneous tube is slid through the lumenof the cap and into the lumen of the outer subcutaneous tub.

This embodiment, with the inner and outer subcutaneous tubes, can beused in a manner similar to the above-described embodiments and has allof the advantages of the above-described embodiments. In particular, thecatheter can be placed in the patient in a conventional antegrade orretrograde manner so that proximal portions of the catheter extend fromthe patient. The proximal end of the catheter then is trimmed to anappropriate selected length. The integral subassembly of the hub and theinner subcutaneous tube is assembled loosely by the manufacturer withthe integral subassembly of the outer subcutaneous tube and the cap sothat distal end of the inner subcutaneous tube is in and near the distalend of the outer subcutaneous tube. The trimmed proximal end of thecatheter then is telescoped into the lumen at the distal end of theinner subcutaneous tube and is advanced until the proximal end of thecatheter substantially reaches the hub. The hub then is tightenedrelative to the cap and deforms the proximal end of the innersubcutaneous tube inwardly and into engagement with the catheter tocreate a fluid tight engagement.

A catheter can become infected or blocked, and in these circumstancesmust be exchanged. The latter embodiment permits easy replacement of thecatheter without disengaging the outer subcutaneous tube that has beenanchored securely in the patient by the fibrous cuff. In this regard,the subassembly of the hub and the inner subcutaneous tube can beseparated from the cap and the outer subcutaneous tube and can beremoved from the patient. The catheter then can be removed from thesubassembly of the cap and the outer subcutaneous tube and from thepatient. A new catheter then is advanced through the lumens of the capand the outer subcutaneous tube and into the patient. A new subassemblyof a hub and an inner subcutaneous tube then is placed in communicationwith the distal end of the catheter. The new inner subcutaneous tube istelescoped closely through the lumen of the cap and into the lumen ofthe outer subcutaneous tube. The hub and the cap then are tightened andsqueeze the inner subcutaneous tube into engagement with the catheter.This embodiment, with the combination of inner and outer subcutaneoustubes, protects the catheter from ascending infection and is moreeffective at preventing bleeding at the tunnel exit site, as explainedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a first embodiment of a catheter inaccordance with the subject invention.

FIG. 1B is a variation of the embodiment of the FIG. 1A.

FIG. 2 is a schematic view of a cuff that can be used with the catheterof FIG. 1B.

FIG. 3 is a perspective view of an outer belt of the cuff of FIG. 2.

FIG. 4 is a top plan view of an inner belt for the top of FIG. 2.

FIG. 5 is a schematic elevational view of a second embodiment of thecuff for the catheter of FIG. 1B.

FIG. 6 is an enlarged schematic view of locked interengagement for thecuff of FIG. 5.

FIG. 7 is a schematic view of a second embodiment of a catheter inaccordance with the subject invention.

FIG. 8 is a schematic view of a hub for use with the catheter of FIG. 7.

FIG. 9 is a schematic view of a third embodiment of a catheter and hubassembly in accordance with the invention.

FIG. 10 is a schematic elevational view of a cuff for use with thecatheter and hub of FIG. 9.

FIG. 11 is a schematic view of a fourth embodiment of a catheter and hubassembly in accordance with the subject invention.

FIG. 12 is a schematic elevational view of a fifth embodiment of acatheter in accordance with the subject invention.

FIG. 13 is a schematic view of a cuff for use with the catheter of FIG.12.

FIG. 14 is a cross-sectional view taken along line 14-14 in FIG. 13.

FIG. 15 is a schematic elevational view of a cuff for use with thecatheter of FIG. 12 and the cuff of FIG. 13.

FIG. 16 is a schematic view of a hub in accordance with a sixthembodiment.

FIG. 17 is a schematic view of a hub in accordance with a seventhembodiment.

FIG. 18 is a schematic view of a cuff tube in accordance with an eighthembodiment.

FIG. 19 is a schematic view of a ninth embodiment where the cuff tubefunctions as a compression cap for compressing the hub.

FIG. 20 is a schematic view of a tenth embodiment with a slit cuff tube.

FIG. 21 is a schematic view of an eleventh embodiment with a distallytrimmable catheter.

FIG. 22 is a schematic view of a tool for separating the cuff from scartissue.

FIG. 23 is a schematic view of a twelfth embodiment in an explodedcondition.

FIG. 24 is a schematic view of the twelfth embodiment in a fullassembled condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A dialysis catheter assembly in accordance with a first embodiment ofthe invention is identified generally by the numeral 10 in FIG. 1A. Thecatheter assembly 10 includes a catheter 12 with a proximal end 14 and adistal end 16. The proximal end 14 will be disposed externally on thepatient, while the distal end 16 will be positioned at a selectedlocation in a blood vessel of the patient, and preferably in closeproximity to the heart of the patient. A subcutaneous tube 20 is mountedover a portion of the catheter 12 near the proximal end 14. Thesubcutaneous tube 20 will be disposed in a subcutaneous tunnel extendingfrom a location on the chest of the patient to a location near the neckof the patient. The tube 20 includes a proximal end 22 that will bedisposed externally of the patient and a distal end 24 that will be inthe subcutaneous tunnel. A polyester cuff 26 or other fibrosing agent isdisposed near the distal end of the tube 24 and is configured to promotethe growth of scar tissue that will hold a catheter assembly 10 in placein the subcutaneous tunnel in the patient. The cuff 26 preferably ispermanently disposed on the tube 20 by the manufacturer, and hencerequires no preoperative or intraoperative manipulation by medicalpersonal. However, as explained herein the cuff 26 can be designed foreasy mounting by the doctor. The tube 20 may further include indicia 28to mark a depth of insertion of the tube 20 into the patient.Additionally, the tube 20 may include a substantially transparent window30. The catheter 12 may further include indicia to mark dimensions andhence volumes from the distal end 16 of the catheter 12. The markings onthe catheter 12 can be visible through the window 30 in the tube 20disposed externally of the patient. A doctor can rely upon these visibleobservations to determine an appropriate volume of heparin solution thatshould be inserted into the assembly 10 to prevent clotting.

A compression cap assembly 32 is mounted over the proximal end 22 of thetube 20 and includes a cap 34 with a passage 36 extending therethrough.The proximal end of the passage includes an annular groove 38 and anarray of internal threads 40. The compression cap assembly 32 furtherincludes a compression sleeve 42 with an annular rib 44 trapped in theannular groove 38 of the passage 36 through the cap 34. Thus, thecompression sleeve 42 is rotatable in the compression cap 34, but istrapped axially. The compression sleeve 42 further includes a passage 46dimensioned to permit the catheter 12 to be passed therethrough.

The assembly 10 further includes a hub assembly 50 that can be threadedinto engagement with the internal threads 40 on the cap 34. Two cannulas50 a project from the hub assembly 50 and are dimensioned for insertioninto the respective lumens in the catheter 12. Tubes 50 b extendproximally from the hub assembly 50 and communicate respectively withthe cannulas 50 a. Luer lock fittings 50 c are secured to ends of thetubes 50 b remote from the housing of the hub assembly 50 and clamps 51are mounted to the respective tubes 50 b distally of the Luer lockfittings 50 c. The clamps 51 are operative to selectively close thetubes 50 b. Threaded engagement of the hub 50 into the cap 34 compressesthe catheter 12, securely holds the catheter 12 and attaches the entirecompression cap assembly 32 to the catheter 12. The catheter assembly ofFIG. 1A is implanted substantially in the conventional manner describedabove. However, the subcutaneous tube 20 is telescoped over the proximalend of the catheter 12 and into the subcutaneous tunnel prepared by thesurgeon after the catheter 12 has been positioned. The tube 20 isadvance so that the distal end 24 of the tube is in a subcutaneousposition in the prepared tunnel and spaced from the vein that has beenaccessed by the catheter 12. The surgeon then trims proximal portions ofthe catheter 12 near the proximal end of the compression cap assembly32. Excess 12 e of the catheter 12 then may be discarded. The cannula 50a of the hub assembly 50 then are passed into the lumens of the dialysiscatheter 12 and the hub assembly 50 is threaded into engagement with thecompression cap assembly 32. As a result, the surgeon is assured ofhaving a precise desired tip to cuff length and a desired precisepositioning of both the proximal and distal ends 14 and 16 of thecatheter 12.

FIG. 1B shows an alternate dialysis catheter assembly that is identifiedgenerally by the numeral 10B. The assembly 10B is very similar to thedialysis catheter assembly 10 described above and illustrated in FIG.1A. However, the dialysis catheter assembly 10B has no equivalent to thesubcutaneous tube 20. As a result, the polyester cuff 26 or otherfibrosing agent is mounted directly on the catheter 12. Additionally,the compression cap assembly 32 is mounted directly on the catheter 12.With this FIG. 1B design option, the polyester cuff 26 cannot be mountedby the manufacturer and must be mounted by medical personalpreoperatively or intraoperatively. The following paragraphs describeseveral optional configurations of cuffs that can be mounted easily tothe catheter 12.

One embodiment of the cuff 26 is illustrated in greater detail in FIGS.2-4. The cuff 26 include a hollow outer belt 52 and an inner belt 54.The outer belt 52 preferably has polyester at least on the exterior. Theinterior of the hollow belt 52 preferably is formed to have a highfriction surface. The inner belt 54 is configured to slide through theouter belt 52. The inner belt 54 has an arrow-shaped projection 56 onone end and a correspondingly configured recess 58 on the opposed end.Additionally, the inner belt 54 has a length that permits the projection56 and the recess 58 to project slightly beyond the opposite ends of theouter belt 52. The inner belt 54 can be slid through the outer belt 52by the manufacturer of the cuff 26 and can be configured as a ring bysnapping the projection 56 into the recess 58. The assembled belts 52and 54 thus are wrapped and secured around a portion of the tube 20 nearthe distal end 24.

FIGS. 5 and 6 show an alternate cuff 26A. The cuff 26A is functionallysimilar to the cuff 26 illustrated in FIGS. 2-4. However, the cuff 26Aincludes interengagable teeth 60 that lock together when the cuff isflexed from the initial substantially linear condition into the annularcondition. As in the embodiment of FIGS. 2-4, the cuff 26A of FIGS. 5and 6 is dimensioned to securely engage on the tube 20. Additionally,both the cuff 26 and the cuff 26A may function to hold the tube 20 inposition on the catheter 12.

A catheter in accordance with the second embodiment of the invention isidentified by the numeral 62 in FIG. 7. The catheter 62 includes aproximal end 64 and a distal end 66. Portions of the catheter 62adjacent the proximal end 64 are formed with non-cylindrical externalsurface configurations 68. In a preferred embodiment, as shown in FIG.7, the exterior of the catheter 62 near the proximal end 64 includes analternating arrangement of conical surfaces 68A intersecting radialsurfaces 68B. Thus, a Christmas tree pattern is formed. The catheter 62is used with a hub 70, as shown in FIG. 8. The hub 70 has a proximal end72, a distal end 74 and a passage 76 extending therebetween. The passage76 includes surface configurations that mate with the external surfaceconfiguration 68 near the proximal end 64 of the catheter 62. As aresult, the proximal end 64 of the catheter 62 can be urged in adistal-to-proximal direction into the distal end 74 of the hub 70. Thisdistal-to-proximal movement of the catheter 62 into the hub 70 isrelatively easy. However, the radially aligned surfaces 68B of theChristmas tree configuration prevent the reverse movement, and henceprevent separation.

The hub 70 further includes tubular members 78 that can be connectedwith a dialysis machine. Additionally, the hub 70 includes the cuff 26described above. The cuff 26 extends around the hub 70 for holding thehub 70 in secure engagement with the catheter 62. The catheter 62 andthe hub 70 are used by trimming the proximal end 64 of the catheter 62to an appropriate length and then inserting the trimmed proximal end 64of the catheter in a distal-to-proximal direction into the open distalend 74 of the hub 70. The surface configurations 68 and 76 engage toprevent separation. The cuff 26 then is mounted around the hub 70 tohold the hub 70 and the catheter 62 together. Implantation proceeds asin the known art.

A third embodiment of a hub in accordance with the subject invention isidentified generally by the numeral 80 in FIG. 9. The hub 80 has aproximal end 82, a distal end 84 and a passage 86 extendingtherethrough. A notch 88 is formed on the outer surface of the hub 80near the distal end 84. A cuff 90, as shown in FIG. 10, can be pressedover the distal end 84 of the hub 80 and forcibly retained in the notch88 to compress the hub 80 into engagement with the catheter 12. Thisassembly can be used substantially as with the previous embodiments andensures that the distal end 16 of the catheter 12 can be positionedprecisely and that the cuff 90 can be disposed at the preferred positionfor anchoring in the tunnel.

FIG. 11 shows a fourth embodiment with a catheter and hub assembly 92that includes a catheter 94 with a proximal end 96 and a distal end 98.A plurality of arrays of external surface irregularities 100 areprovided at spaced intervals on the catheter 94. Additionally aplurality of cuffs 102 are provided at spaced intervals on the catheter94. The assembly 92 further includes a hub 104 that can be structurallysimilar to the hub 70 shown in FIG. 8. The catheter 94 can be trimmed toan appropriate length and the appropriate array of external surfaceregularities 100 then are inserted into locked engagement in the hub 104substantially as described with respect to the embodiment of FIGS. 7 and8.

A fifth embodiment of the subject invention is shown in FIGS. 12-15 andincludes a catheter 110 with a proximal end 112 and a distal end 114.External surface regions of the catheter 110 extending distally from theproximal end 112 are formed with an array of external threads 116. Acuff ring 118 includes an array of internal threads 120 configured forthreaded engagement with the threads 116 on the catheter 110, as shownin FIGS. 13 and 14. External surface areas of the cuff 118 include apolyester material that promotes growth of scar tissue for anchoring thecatheter 110. The catheter 110 also is used with a hub 122. The hub 122includes an array of internal threads 124 configured for mating with theexternal threads 116 on the catheter 110. The hub 122 further includescannulas 126 that can engage in the lumen that pass through the catheter110. The assembly shown in FIGS. 12-15 is used in a manner very similarto the embodiments depicted in FIGS. 1-11 and described above. Inparticular, portions of the catheter 110 adjacent the proximal end 112are trimmed to an appropriate length that will achieve properpositioning of the distal end 114 of the catheter 110. The cuff 118 thenis threaded onto the catheter 110 and is advanced from the trimmedproximal end 112 towards the distal end an appropriate amount for properpositioning of the cuff 118. The hub 122 then is threaded intoengagement with the trimmed proximal end 112 of the catheter 110.

A variation of the embodiment shown in FIGS. 12-15 is depicted in FIG.16. In particular, FIG. 16 shows a hub 132 with a cuff 134 permanentlyaffixed thereto. The hub 132 has an array of internal threads 136 thatcan be threaded into engagement with the external threads 116 on thecatheter 110 depicted in FIG. 12.

FIG. 17 shows a hub 140 that can be used with the catheter 12 describedabove and illustrated in FIG. 1. The hub 140 has a proximal end 142 anda distal end 144. Interior surface regions of the hub 140 are notthreaded. However, the hub 140 includes an array of external threads146. A cap or nut 148 is threadedly engaged with the external threads146 on the hub 140. The nut 148 can be advanced in a proximal-to-distaldirection and functions to tighten the hub 140 against the catheter 12inserted therein. FIG. 17 shows a polyester cuff 152 mounted to theexterior of the hub 140 near the distal end 144. The mounting of thecuff 152 of the hub 140 can be by any of the above-described mountingmeans, including threaded engagement or snapped engagement into a grooveor an arrangement where an initially linear cuff is wrapped around andlocked into engagement around the hub.

FIG. 18 shows a further embodiment with a cuff tube 150 having aproximal end 152, and distal end 154 and a lumen extending between theends. The lumen is configured for telescoping the cuff tube 150 over acatheter 156. The catheter 156 may be substantially identical to thecatheter 12 described and illustrated with respect to the firstembodiment. A cuff 158 is mounted around the cuff tube 150 near thedistal end 154. In this regard, the cuff 158 can be mounted permanentlyto the cuff tube 150 with adhesive or the like applied by themanufacture of the cuff tube 150. Alternatively, any of the abovedescribed cuffs can be mounted to the cuff tube 150 by medical personalimmediately prior to the deploying the cuff tube 150. With this latteroption, the distal end 154 of the cuff tube 150 can be slitlongitudinally so that the mounting of the cuff 158 thereon compressesthe cuff tube 150 for at least partial retention of the cuff tube 150 onthe catheter 156.

Hub attachments structures 160 are formed on the cuff tube 150 near theproximal end 152. In the illustrated embodiment, the hub attachmentstructure 160 is an annular rib with a sloped proximal face 160A and aradially aligned distal face 160B. A compression belt 162 is mountedaround the cuff tube 150 near the proximal end 152 for squeezingproximal portions of the cuff tube 150 inwardly into the securemechanical and fluid tight engagement with the catheter 156. Otherattachments means can be employed in place of the compression belt 162,such as the known hose clamp for attaching a compressible hose to anipple. In this regard, reference is made to the MSC Industrial SupplyCo. catalog identified above and incorporated herein by reference.

The assembly of FIG. 18 further includes a hub 164. The hub 164 includesa distal end 166 with mounting structures 168 for securely engaging thehub 164 with the locking structure 160 on the cuff tube 150. Thecatheter assembly shown in FIG. 18 is employed by utilizing a catheter156 that is assured to have at least the maximum required length. Thecatheter 156 is inserted so that the distal end of the catheter 156 isproperly positioned in the patient and so that the proximal end of thecatheter 156 extends from patient. The cuff tube 150 then is telescopedover the catheter 156 so that the cuff 158 is at a desired position foranchoring in the patient by scar tissue that will grow around the cuff158. The compression belt 162 or other attachment means then istightened on or near the proximal end 152 of the cuff tube 150. Aproximal excess portion 156 e of the catheter 156 then is trimmed at ornear the proximal end 152 of the cuff tube 150. The hub 164 then istelescoped over the proximal end 152 of the cuff tube 150. As a result,the attachment structures 168 near the distal end 166 of the hub 164securely engage the attachment structures 160 on the cuff tube 150.

The configurations of the cuff tube and the hub can vary from thoseshown in FIG. 18. For example, FIG. 19 shows a cuff tube 150 a formedfrom a hard plastic and having proximal end 152 a, a distal end 154 aand lumen 156 a extending between the ends. A polyester cuff 158 a orother fibrosing agent is mounted around the cuff tube 150 a near thedistal end 154 a. The lumen 156 a includes a tapered entry 160 aadjacent the proximal end 152 a. Additionally, an annular locking groove162 a is formed immediately adjacent to and distally of the taperedentry 160 a. The cuff tube 150 a is used with a hub assembly 164 a thatis structurally and functionally similar to the hub assembly 50described above with respect to FIG. 1. However, the hub assembly 164 ais formed from a material that is softer and/or thinner than the hardplastic of the cuff tube 150 a. Hence, the hub assembly 164 a is morereadily compressible than the cuff tube 150 a. The hub assembly 164 aincludes a distal end 166 a and a conically tapered portion 168 aadjacent the distal end 166 a. The conically tapered portion 168 aflares outwardly to greater cross sections at distances further from thedistal end 166 a. The catheter 169 a is inserted through the tube 150 aand trimmed to a preferred length, as described above. The excess of thecatheter then is discarded, and the hub 164 a is inserted into the cufftube 150 a. The tapered shape the surface 168 a on the hub assembly 164a and the tapered entry 160 a at the proximal end 152 a of the cuff tube150 a are substantially complementary. As a result, and in view of thethinner/softer material of the hub 164 a, portions of the hub assembly164 a near the distal end 166 a will be compressed inwardly into secureengagement with the catheter 169 a. The large diameter end of thetapered portion 168 a will be engaged in the locking groove 162 a. Thisvariation will avoid the need to employ a separate compressive belt orother such attachment means for securing the cuff tube to the catheter.

A further variation of the catheter assembly of the subject invention isillustrated in FIG. 20. This embodiment employs a conventional catheter12 comparable to the catheter shown in FIG. 1. A C-shaped cuff 170 ismounted on a slit cylindrical cuff positioning tube 172. In thisembodiment, the catheter 12 is positioned as described above. The slittube 172 is mounted over the catheter 12 and is moved distally along thecatheter 12 in the direction of arrow A until the cuff 170 is anappropriate position. The tube 172 then is snapped together by securingopposed longitudinal edges of the slit tube 172 together. Innercircumferential surfaces of the tube may be coated or lined with amaterial that will ensure fluid tight fit of the tube 172 to thecatheter 12. The catheter 12 can be trimmed at the proximal end and ahub can be mounted as in other embodiments.

FIG. 21 as shows another variation of the assembly for assuring accuratepositioning of the tip of the catheter. In this regard, the catheter 180is provided with a length that exceeds the maximum anticipated length. Ahub assembly 182 is provided at proximal end of the catheter 180 and acuff 184 is mounted in slightly spaced relationship to the hub assembly182. Distal portions of the catheter 180 are cut to achieve anappropriate length, and the extreme distal end 180 e that is cut fromthe catheter 180 then is discarded. One lumen 186 of the catheter 180 iscut in a distal position and the excess 186 e is discarded so that thelumen 186 is shorter than the catheter 188. The tube lumen then may beseparated from one another. The catheter 180 can be inserted in aconventional manner and ensures proper positioning of both distal andproximal ends of the catheter relative to the patient withoutmaintaining a complicated inventory of parts.

Catheter assemblies may require removal. As noted above, prior artcatheters have required a complicated dissection of the cuff from thepatient. The catheter assembly of the subject invention, however, may beused with a cuff removal tool 190, as shown in FIG. 22. In particular,the cuff removal tool 190 is a generally slit tubular structure with aproximal end 192 and a distal end 194. The proximal end 192 isconfigured to define a handle and is roughened or knurled to facilitatemanipulation and turning of the tool 190. The distal end 194 defines anarray of sharp cutting teeth. The tool 190 is used by telescoping theproximal end 194 of the tube 190 over the catheter. This mounting of thetool 190 over the catheter can be achieved by transversally movingportions of the catheter through the slit 196 defined in the tube 190.The tool 190 then is rotated so that the teeth cut the scar tissue. Thusthe catheter can be removed easily.

FIGS. 23 and 24 show an embodiment of the invention similar to theembodiment shown in FIG. 1A. More particularly, the embodiment of FIGS.23 and 24 is used with a catheter 12 substantially identical to thecatheter 12 of the embodiment shown in FIG. 1A. The catheter 12 includesa proximal end 14, a distal end 16 and lumens extending between theends. The embodiment of FIGS. 23 and 24 further includes a hub assembly50 that is substantially identical to the hub assembly of the embodimentshown in FIG. 1A. However, the metal cannulas 50 a of the hub 50 projectfarther in the distal direction in the embodiment of FIGS. 23 and 24.Still further, the embodiment of FIGS. 23 and 24 includes an outersubcutaneous tube 20 that is substantially the same as the subcutaneoustube 20 of the embodiment shown in FIG. 1A. In this regard, the outersubcutaneous tube 20 has a proximal end 22, a distal end 24 and a lumen29 extending between the ends. A polyester cuff 26 or other fibrosingagent is disposed around the outer circumferential surface of the outersubcutaneous tube 20 at locations near the distal end 24. A cap 34 has adistal end mounted permanently to the proximal end 22 of the outersubcutaneous tube 20 so that the cap 34 and the outer subcutaneous tube20 define an integral subassembly. The cap 34 also has a proximal endand a lumen 36 extending between the ends. Portions of the lumen 36 atthe proximal end of the cap 34 have threads 40 for threadedly engagingthreads on the hub 50.

Unlike the embodiment of FIG. 1A, the embodiment of FIGS. 23 and 24further includes an inner subcutaneous tube 200. The inner subcutaneoustube 200 has a proximal end 202, a distal end 204 and a lumen 206extending between the ends. The lumen 206 of the inner subcutaneous tube200 is configured and dimensioned so that the proximal end 14 of thecatheter 12 can be inserted into the lumen 206 of the inner subcutaneoustube 200. The inner subcutaneous tube 200 has an outer circumferentialsurface 208 that is dimensioned cross-sectionally to be receivedslidably in the lumen of the outer subcutaneous tube 20. In this regard,portions of the lumen of the outer subcutaneous tube 20 preferably arereduced to a slightly smaller inside diameter at the distal end 24 topress the inner subcutaneous tube inwardly for achieving closeengagement between the outer subcutaneous tube 20, the innersubcutaneous tube 200 and the catheter 12 and for preventing fluid flowbetween these three tubular members. Portions of the inner subcutaneoustube 200 adjacent the proximal end 202 preferably are flared outwardlyslightly and are engaged permanently with the hub 50 so that the hub 50and the inner subcutaneous tube 200 define an integral subassembly. Theinner subcutaneous tube 200 also has a transparent window 230 registeredwith the window 30 in the outer subcutaneous tube 20 to permitobservation of the catheter 12 for accurately gauging the volume ofheparin solution that should be inserted into the assembly. The metalcannulas 50 a that extend from the hub 50 are dimensioned in thisembodiment to project to the distal end 204 of the inner subcutaneoustube 200.

The embodiment of the invention depicted in FIGS. 23 and 24 is used byfirst inserting the distal end 16 of the catheter 12 into the patient ina conventional manner. The insertion of the catheter 12 can be performedin an antegrade or retrograde manner. Portions of the catheter 12adjacent the proximal end 14 are trimmed to a length appropriate for thepatient.

The physician then accesses an assembly that comprises the integralsubassembly of the hub 50 and the inner subcutaneous tube 200 looselyengaged with the integral subassembly of the cap 34 and the outersubcutaneous tube 20. More particularly, the hub 50 is assembledpermanently (e.g. adhered or welded) with the inner subcutaneous tube200 by the manufacturer. Similarly, the cap 34 is assembled permanently(e.g. adhered or welded) to the outer subcutaneous tube 20 by themanufacturer. Additionally, the outer and inner subcutaneous tubes 20and 200 are telescoped together by the manufacturer and the threads 40of the cap 34 are loosely engaged with the threads of the hub 50. Thetrimmed proximal end 14 of the catheter 12 then is inserted into thedistal end 204 of the inner subcutaneous tube 200 and into communicationwith the metal cannulas 50 a of the hub 50. The hub 50 and the cap 34then are tightened threadedly relative to one another to achieve theconnected state shown in FIG. 24. As a result, the cap 34 squeezes theproximal end 202 of the inner subcutaneous tube 200 and deforms theinner subcutaneous tube 200 inwardly for securely holding the catheter12 in the lumen 206 of the inner subcutaneous tube 200 and for achievinga fluid-tight seal between the inner subcutaneous tube 200 and thecatheter 12. This assembly then is advanced distally so that the distalend 24 of the outer subcutaneous tube 20 advances into the subcutaneoustunnel prepared in the patient and so that the fibrous cuff 26 reaches aposition for secure anchoring in the patient due to tissue ingrowth intothe cuff 26.

A dialysis catheter occasionally must be replaced due to infection orblockage. In the prior art, the entire assembly would have to beremoved, and this procedure would require separating the fiber cuff fromthe tissue of the patient that had grown into the fiber cuff. This is asomewhat complicated and invasive procedure. However, the embodiment ofthe invention depicted in FIGS. 23 and 24 avoids the complicationsassociated with any required exchange of the catheter. Moreparticularly, the catheter 12 of FIGS. 23 and 24 can be replaced merelyby unthreading the hub 50 from the cap 34 at the proximal end of theouter subcutaneous tube 20. The integral subassembly of the hub 50 andthe inner subcutaneous tube 200 then merely is removed from the patientwithout dislodging the outer subcutaneous tube 20. The catheter 12 thenis removed without dislodging the outer subcutaneous tube 20. A newcatheter 12 then is inserted through the lumen of the outer subcutaneoustube 20 and at least partly towards it final position in the bloodvessel of the patient. The proximal end 14 of the new catheter 12 thenis trimmed to an appropriate length. The trimmed proximal end 14 of thereplacement catheter 12 then is placed in communication with a newsubassembly that comprises a new subcutaneous tube 200 and a new hub 50.The new catheter 12, the new inner subcutaneous tube 200 and the hub 50then are advanced distally to the final position in the patient and aretightened into the cap 34 at the proximal end 22 of the previouslyanchored outer subcutaneous tube 20.

The embodiment of the invention depicted in FIGS. 23 and 24 has theadvantages described with respect to the previous embodiments as well asadditional advantages. In this regard, the embodiment of the inventiondepicted in FIGS. 23 and 24 enables a precise control for thepositioning both the tip at the distal end of the catheter 12 and cuff26 on the outer subcutaneous tube 20. As in the prior embodiments, theembodiment of the invention depicted in FIGS. 23 and 24 avoids the needfor a large inventory of catheters 12 of different lengths that must beselected in view of the size of the patient. The embodiment of theinvention depicted in FIGS. 23 and 24 also is well suited for bothantegrade and retrograde insertion of the catheter 12 in the patient.Furthermore, the embodiment of the invention depicted in FIGS. 23 and 24permits an easy exchange of a catheter 12 that has become infected orblocked. The use of inner and outer subcutaneous tubes 20 and 200, asdepicted in FIGS. 23 and 24, also is very effective at protecting thecatheter 12 from ascending infection. Still further, the illustrated useof two subcutaneous tubes 20, 200 is effective at preventing bleeding atthe exit site of the subcutaneous tunnel. Additionally, and importantly,the outer subcutaneous tube 20 has an inside diameter that exceed theoutside diameter of the catheter 12 by the radial thickness of the innersubcutaneous tube 200. Thus, the outer subcutaneous tube 20 will notscrape off the fibrin sheath that accumulates on the outer surface ofthe catheter 12, and the catheter 12 can be removed without producingdebris that might otherwise remain in the patient.

Any of the above-described cuffs or variations thereof may comprise orconsist of a fibrosing agent. Known fibrosing agents include, but arenot limited to silk, collagen, talc, talcum powder, beryllium, copper,silica, quartz, EVA, PLA, polyurethanes and polymerized drugcompositions. A discussion of fibrosing agents is provided in publishedU.S. Patent Appl. Pub. No. 2005/0191248 the disclosure of which isincorporated herein by reference.

1. A catheter assembly for at least semi-permanent retention in apatient, said assembly comprising: an elongate catheter having aproximal end for disposition externally of the patient, a distal end fordisposition in the patient and at least one lumen extending between theends, the proximal end of the catheter being trimmable for achieving aselected length between the proximal and distal ends of the catheter; afirst subassembly having a hub and an inner subcutaneous tube with aproximal end connected to the hub, a distal end and a lumen extendingbetween the ends, the lumen of the inner subcutaneous tube beingslidably disposed over portions of the catheter adjacent the proximalend of the catheter; and a second subassembly having an outersubcutaneous tube having opposite proximal and distal ends and lumenextending between the ends, a fibrosing means disposed on the outersubcutaneous tube for promoting a growth of scar tissue for anchoringthe catheter assembly in the patient, the second subassembly furtherhaving a cap with opposite proximal and distal ends and a lumenextending between the ends, portions of the outer subcutaneous tubeadjacent the proximal end thereof being secured to the cap so that thelumens of the cap and the outer subcutaneous tube communicate, thelumens of the cap and the outer subcutaneous tube surrounding a portionof the inner subcutaneous tube, and the cap being releasably engageablewith the hub for squeezing the inner subcutaneous tube into secureengagement with the catheter.
 2. The catheter assembly of claim 1,wherein the hub is threadedly engageable with the cap.
 3. The catheterassembly of claim 2, wherein the distal end of the inner subcutaneoustube extends substantially to the distal end of the outer subcutaneoustube when the cap and the hub are releasably engaged with one another.4. The catheter assembly of claim 3, wherein the hub further comprisesat least one cannula extending therefrom and projecting through theinner subcutaneous tube substantially to the distal end of the innersubcutaneous tube, the cannula projecting from the hub being dimensionedfor telescoping into the lumen of the catheter.
 5. The catheter assemblyof claim 1 wherein the lumen through the inner subcutaneous tube isdimensioned at locations in proximity to the distal end of the innersubcutaneous tube for achieving a substantially fluid tight engagementwith the catheter for preventing fluid flow between the catheter and theinner subcutaneous tube.
 6. The catheter assembly of claim 1 wherein theproximal end of the inner subcutaneous tube is flares outwardly atlocations adjacent the hub.
 7. A method for implanting a catheter in apatient, the method comprising the steps of: providing a catheter havinga proximal end, a distal end and at least one lumen extending betweenthe ends; inserting the catheter in a patient so that the distal end ofthe catheter is at a targeted location in a blood vessel of a patient,the proximal end of the catheter is disposed externally of the patientand an intermediate portion of the catheter passes through asubcutaneous tunnel spaced from the blood vessel; mounting a fibrosingcuff around the intermediate portion of the catheter in the subcutaneoustunnel; trimming portions of the catheter adjacent the proximal end todefine a trimmed proximal end; and affixing a hub to the trimmedproximal end.
 8. The method of claim 7, wherein the step of mounting thefibrosing cuff around the intermediate portion of the catheter comprisesproviding a subcutaneous tube having the fibrosing cuff disposedthereon, sliding the subcutaneous tube into the subcutaneous tunnel andover the catheter prior to trimming the proximal end of the catheter. 9.The method of claim 8, wherein the subcutaneous tunnel has a first endin proximity to the blood vessel and a second end remote from the bloodvessel, the step of inserting the catheter in a patient comprisesinserting the distal end of the catheter into the second end of thesubcutaneous tunnel, passing the distal end of the catheter from thefirst end of the subcutaneous tunnel, and inserting the distal end ofthe catheter into the blood vessel and to the targeted location so thatthe proximal end of the catheter extends from the patient adjacent thesecond end of the subcutaneous tunnel.
 10. The method of claim 8,wherein the subcutaneous tunnel has a first end in proximity to theblood vessel and a second end remote from the blood vessel, the step ofinserting the catheter in a patient comprises, inserting the distal endof the catheter into the blood vessel and to the targeted location sothat the proximal end of the catheter extends from the patient at thesecond end of the subcutaneous tunnel, inserting the proximal end of thecatheter into the subcutaneous tunnel and passing the proximal end ofthe catheter from the subcutaneous tube adjacent the second end of thesubcutaneous tunnel.